LightOJ 1348 Aladdin and the Return Journey (tree link splitting), lightojaladdin

LightOJ 1348 Aladdin and the Return Journey (tree link splitting), lightojaladdin

Tree link splitting template questions.
There have been competitions recently .. I haven't written it for a long time. Obviously unfamiliar .. Find a template question to familiarize yourself.
The Code is as follows:

#include <iostream>#include <string.h>#include <math.h>#include <queue>#include <algorithm>#include <stdlib.h>#include <map>#include <set>#include <stdio.h>using namespace std;#define LL __int64#define pi acos(-1.0)#define root 1, n, 1#define lson l, mid, rt<<1#define rson mid+1, r, rt<<1|1//#pragma comment(linker, "/STACK:1024000000")const int mod=1e9+7;const int INF=0x3f3f3f3f;const double eqs=1e-3;const int MAXN=30000+10;int head[MAXN], cnt, tot, n;int siz[MAXN], dep[MAXN], w[MAXN], top[MAXN], fa[MAXN], son[MAXN];int sum[MAXN<<2];int a[MAXN];struct node{        int u, v, next;}edge[MAXN<<1];void add(int u, int v){        edge[cnt].u=u;        edge[cnt].v=v;        edge[cnt].next=head[u];        head[u]=cnt++;}void init(){        memset(head,-1,sizeof(head));        cnt=tot=0;        memset(sum,0,sizeof(sum));        memset(son,0,sizeof(son));        memset(dep,0,sizeof(dep));}void dfs1(int u, int p){        siz[u]=1;        for(int i=head[u];i!=-1;i=edge[i].next){                int v=edge[i].v;                if(v==p) continue ;                fa[v]=u;                dep[v]=dep[u]+1;                dfs1(v,u);                siz[u]+=siz[v];                if(siz[v]>siz[son[u]]) son[u]=v;        }}void dfs2(int u, int tp){        w[u]=++tot;top[u]=tp;        if(son[u]) dfs2(son[u],tp);        for(int i=head[u];i!=-1;i=edge[i].next){                int v=edge[i].v;                if(v!=fa[u]&&v!=son[u])                        dfs2(v,v);        }}struct Line_Tree{        void PushUp(int rt)        {                sum[rt]=sum[rt<<1]+sum[rt<<1|1];        }        void Update(int p, int x, int l, int r, int rt)        {                if(l==r){                        sum[rt]=x;                        return ;                }                int mid=l+r>>1;                if(p<=mid) Update(p,x,lson);                else Update(p,x,rson);                PushUp(rt);        }        int Query(int ll, int rr, int l, int r, int rt)        {                if(ll<=l&&rr>=r){                        return sum[rt];                }                int mid=l+r>>1, ans=0;                if(ll<=mid) ans+=Query(ll,rr,lson);                if(rr>mid) ans+=Query(ll,rr,rson);                return ans;        }}lt;int SumQuery(int u, int v){        int f1=top[u], f2=top[v], ans=0;        while(f1!=f2){                if(dep[f1]<dep[f2]){                        swap(u,v);                        swap(f1,f2);                }                ans+=lt.Query(w[f1],w[u],root);                u=fa[f1];f1=top[u];        }        if(dep[u]<dep[v]){                swap(u,v);        }        return ans+lt.Query(w[v],w[u],root);}int main(){        int t, u, v, q, i, x, Case=0;        scanf("%d",&t);        while(t--){                scanf("%d",&n);                for(i=1;i<=n;i++){                        scanf("%d",&a[i]);                }                init();                for(i=1;i<n;i++){                        scanf("%d%d",&u,&v);                        u++;v++;                        add(u,v);                        add(v,u);                }                dfs1(1,-1);                dfs2(1,1);                for(i=1;i<=n;i++){                        lt.Update(w[i],a[i],root);                }                scanf("%d",&q);                printf("Case %d:\n",++Case);                while(q--){                        scanf("%d",&x);                        if(!x){                                scanf("%d%d",&u,&v);                                u++;v++;                                printf("%d\n",SumQuery(u,v));                        }                        else{                                scanf("%d%d",&u,&v);                                u++;                                lt.Update(w[u],v,root);                        }                }        }        return 0;}